The invention relates to the new biphenylyl ethers of the general Formula I ##STR2## wherein R.sup.1, R.sup.2 and R.sup.3 are each H or CH.sub.3 ; R.sup.4 is H, F, Cl, Br or CF.sub.3 ; Z (when R.sup.2 = R.sup.3 = H) is piperidino or morpholino each of which is monosubstituted or polysubstituted by alkyl having 1-4 C atoms, and Z (when R.sup.2 = CH.sub.3) is morpholino, pyrrolidino, homopiperidino or piperidino which is optionally monosubstituted or polysubstituted by alkyl having 1-4 C atoms or by a hydroxyl group; and to physiologically acceptable acid addition salts thereof.